This invention relates to a device for extracting and displaying features of a contour image, and more particularly to a device for extraction of features of a contour image which functions effectively such as in the automatic diagnosis of morbid regions in the human liver, for example, by permitting extraction of hepatic deformations due to disease from the contour of the radioisotope image of the liver.
Extraction of features such as bends, curves, recesses and protuberances from the contour of an image constitutes one important measure for the recognition of the shape of an article under examination.
Heretofore, it has been customary to detect variation of a given contour image from the standard image of its kind by successively measuring curvatures of fine segments of the contour and comparing the found values with the standard values. The methods heretofore employed for the pattern recognition are invariably complicated. (For example, T. Pavlidis et al. "Segmentation of Plane Curves" IEEE. Trans. vol. C-23, No. 8, p. 860-870 (1974), A. Rosenfeld et al. "Angle Detection on Digital Curves" IEEE. Trans. vol. C-22, No. 9, p. 875-878, (1973), S. D. Shapiro "Transform Method of Curve Detection for Textured Image Data" IEEE. Trans. vol. C-27, No. 3, p. 254-255 (1978), T. Pavlidis "The Use of a Syntactic Shape Analyzer for Contour Matching" IEEE. Trans. vol. PAMI-1, No. 3 p. 307-310, (1979), J. W. Mckee, et al. "Computer Recognition of Partial Views of Curved Objects" IEEE. Trans. vol. C-26, No. 8, p. 790-800 (1977), R. Jain et al. "Computer Analysis of Scenes with Curved Objects" Proc. IEEE. vol. 67, No. 5, p. 805-812 (1979)).